When i use 4x4, the front axle will not engage, I think!!! The drive shaft turns from transfer case to axle, but there is a grinding noise from the front end. Could that be from a vacuum leak? or is the gears shot?

When i use 4x4, the front axle will not engage, I think!!! The drive shaft turns from transfer case to axle, but there is a grinding noise from the front end. Could that be from a vacuum leak? or is the gears shot?


Need year,, make, model and engine Dale

89 cherokee 4.0Litre, the front end sounds like it is not engage all the way! Sometimes it goes in. so could it be vacuum leak?

The first thing you want to check......
ALL VACUMN LINES,AND THE VACUMN CANNISTER LOCATED BEHIND THE FRONT BUMPER,PASSENGER SIDE
The hard plastic lines break easily,check all the lines,there are some that
run under the battery tray.Check all the way to the firewall.Any breaks can be spliced w/ 5/32"gasline hose.
IF the cannister has been hit or damaged it may need to be replaced.Where you might find one,haven't got a clue.Most of the ones in salvage yards are either taken or FUBARED
In the area where the heater hoses go into the firewall,there is a 3 way vacumn connecter,this goes to the x fer case.IF any of the lines are broken,the x fer case will not engage the front wheels.

Thanks for the info regarding the vacuum system. The Haynes manual I have has sad little information regarding the vacuum system other than schematics as they apply to emission control.
As for schematics pertaining to the heating system, four wheel drive engagement and all the components (i.e. Vacuum canister, which, technically, on an 88 Cherokee shouldn't be there according to the manual)
Any idea where I can pick up an aftermarket vacuum system schematic?

Stephen